Pressure-indicator.



W. H; SAUVAGE.

PRESSURE INDICATOR, APPLICATION Pimm JUNE 25, um,

W. H. SAUVAGE. PRESSURE INDICATOR. APPLIUA'TION :FILED JUNE z5, 1912.

Patented Aug. 11, 1914..

2 SHEETS-SHEET 2.

shown in Fig. 5.

entran WILLIAM H. SAUVAGE, or New YORK, N. Y., AssIeNoR rro SAUVAGE-WARD BRAKE COMPANY, INC., A CORPORATION or DELAWARE.

y* V, i Specification `ofmlett'ers `Patent. spline-timmeren 19121 j semina. 705,764.

Patented 11mg. 11, 19141.

To GIZ whom t may concern Be a known that nwmanfafsienes;

is a speciication, reference being had to theY accompanying drawings, which, forma part: hereof. f

This invention relates yparticularly'"to 'the construction of pressure indicators for use in connection with HuidI pressure brake systems on railway cars and for other uses in which .the pressure indicatorwis' exposed to the danger of being Stolen, rassurantits value for other purposes, todangerloffbi ing broken by Hying pieces of. ballast, etc., and to the certainty of being so obscured by dust, snow or ice as to'be unreadable.

The object of the invention is to provide a pressure indicator which is not likely to be stolen, is not likely to be broken, and is not likely to be rendered -illegible by dust.

In accordance with the invention the indicator is strongly constructed without glass being broken by flying stones and with the indicating scale normally covered and exposed only by relative movement of the scale and the inclosing part.

The invention will be more fully explained hereinafter with reference to the accompanying drawings in which it is illustrated and in which- Figure 1 is a top View of a portion of a fluid pressure brake system suiicient to illustrate the application of the invention thereto, the car body being indicated by dotted lines. Fig. 2 is a viewin elevation of the pressure indicator. in section on the plane-indicated by the4 line 3-3 of Fig. 2. Fig. 4 is a view similar to Fig. 3 but showing a .slightly ditl'erent internal construction. Y Fi' J5 is a-view illustrating the application of t e indicator directly to the brake cylinder. Fig. 6 is a detail view in section, on a larger scale, ofthe indicator In the construction represaented"V in Fig. 1 the usual brake cylindera, shown chiefly in dotted lines, is connected, 'as usual, by a pipe b, to the auxiliary reservoir c "and thence with the rest of the brake system. 0n the brake cylinder or auxiliary reservoir or any convenient point in the yconnection Fig. 3 is a detail View` between them is located the indicator d by which the pressure at any time may be determined. In the form of the indicator shown in Figs. 2 and 3, a short cylinder or ,Casing e 1s connected, as indicated atA c', to

the line in which the pressure is to be determined, and as marked on its exterior, has at e2 (shown in dotted lines in Fig. 2), a

.reading scale, preferably by rather deep grooves`formed circumferentially about the cylinder. Within the cylinder is a piston f which is subject to the pressure of a spring g. The latter abuts against a screw plug fr in the end of the cylinder. The stem or rod f of the piston is extended through the screw plug L and carries a cap i which has a depending flange z" surrounding the cylinder e and covering and protecting the scale e2 thereon. The pressure of the air against the piston f moves it against the resistance of the spring f and the degree of the pressure-is indicated by the lower edge or end of the flange z" on the scale e2. It will be noted that all of the parts are reasonably heavy and strongly constructed and especially that the scale is covered by the flange z" of the cap z' and is thereby protected against obliteration by dust and dirt. Not only does the cap cover the scale when there is no pressure in the cylinder, but as it returns to normal position after having been displaced it rubs olf such dust as may have accumulated on the scale while it was exposed. It is therefore easy at all times to obtain a reading of the scale.

In the embodiment of the invention shown in Fig. 4 the construction is substantially the same as that already described,"the cylinder e being connected through a pipe e' with the brake system and having a scale e2 formed on its exterior. The 'piston f is likewise connected -by its stem or rod f with 'a cap i which has a depending flange t" to part with the head a of the brake cylinder a, so that the indicator forms a part of then cap n, threaded upon the cylinder a?, fur-V nishes an abutment for the spring. The stem or rod m of the piston passes :freely through the cap n and maybe provided out side of the cap with a dust guard or ring m2. In this case, the scale m3 is formed on the piston rod or stem. It is protected by the cylinder itself and is exposed by relative movement of the piston with respectto thc cylinder.

Various other embodiments of the invention will suggest themselves to suit different conditions of use.

I claim as my invention A pressure indicator which comprises a cylinder in communication at one end with the source of air pressure and provided on its outer periphery with a series of circum l 4 ferential grooves constitutin a reading `seale,a piston within the cy 1in er subject on ones'ide to the pressure o the air, a-spiral spring in operative engagement with the other side of the piston, a plug threaded removably into the open Vend of the cylinder and` constituting a seat for said spring whereby the spring and the piston are entirely incased, anda slidable cap in snug engagement with the outer walls of the cylinder and:l adapted normally to cover the reading scale, the stem of the piston extending through an aperture in the' removable plug and being fastened -to the cap whereby upon movement of the piston under air pressure the cap-is-moved correspondinglyand itslower edge passesfoverthe grooves lofthe reading scale to uncover the same and indicate the pressure acting against the piston, the spring serving vto restore the piston 1 and the'cap to their normal positions when .i

lthe piston is relieved from 'the pressure `of the air, the edge of the cap on such return movement serving to remove all foreign substances from the reading scale. Y

lThis specification signed and witnessed this 20th day of June A. D., 1912.

Y WILLIAM H. SAUVAGE.. Signed in the presence of E. M. TAYLOR, WoR'rHING'roN CAMPBELL. 

